Method of controlling a brush chipper

ABSTRACT

An improved brush cutter having an upper feed control member with stop, forward, neutral, and reverse positions also has a lower feed stop member with selectable sensitivity. Another aspect of the invention is to predict the feed roller shutoff point according to the rate of engine deceleration. According to another aspect, when the feed rollers stop feeding material into the cutters, to overcome drag on the cutters, a controller stops the feed rollers and then reverses them for a short time, and then reverses the rollers again if the problem is still present. To prevent jamming, a pressure switch senses when oil in a hydraulic motor system for rotating the feed rollers is too high and the controller momentarily reverses the feed rollers and then causes them to go forward, a cycle which can occur several times until the feed rollers are no longer stalled. By another aspect of the invention, the controller senses characteristics of the brush cutter and chooses an operating system based on the characteristics sensed. The controller can also sense if the brush chipper has not been used for a predetermined period of time and automatically reduce the idle speed of the engine until the brush chipper is used again, and then automatically return the engine to a normal idle speed before the feed rollers will pull brush into the brush chipper.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. Ser. No. 11/692,439 filed Mar.28, 2007, entitled METHOD OF CONTROLLING A BRUSH CHIPPER, which is aDivisional of U.S. patent application Ser. No. 11/416,422 filed May 2,2006, entitled IMPROVED BRUSH CHIPPER AND METHODS OF OPERATING SAME, nowU.S. Pat. No. 7,232,083 issued Jun. 19, 2007, which is a Divisional ofU.S. patent application Ser. No. 10/001,509 filed Oct. 31, 2001,entitled IMPROVED BRUSH CHIPPER AND METHODS OF OPERATING SAME, now U.S.Pat. No. 7,044,409 issued May 16, 2006, which claims the benefit of U.S.patent application Ser. No. 60/246,670 filed Nov. 8, 2000, entitledMETHOD AND APPARATUS FOR OPERATING A BRUSH CHIPPER USING PREDICTABILITYOF RPM, REVERSING OF FEED ROLLS, OPTIMIZING ENGINE RPM, OVERCOMINGJAMMING AND SELF DIAGNOSIS, now expired, and are all incorporated byreference herein in their entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

One aspect of the present invention relates generally to brush chipperswhich have a manually controlled upper feed stop member with fourpositions, which sequentially from forward to rear of the upper feedstop member are stop, forward, neutral and reverse, and a lower feedstop member which serves to shut off the feed mechanism of the brushchipper when it is moved forwardly by a predetermined distance or angle.This aspect of the present invention relates more particularly to such abrush chipper wherein the lower feed stop member has more than one stopposition and specifically wherein the operator can adjust the stopposition between one or more positions to make it more sensitive or lesssensitive, depending upon the working conditions. The present inventionalso relates to such a lower feed stop member having a feature to re-setit to a predetermined setting after each use of the brush chipper. Otheraspects of the invention relate to predictability, feed roller stop andreverse, overcoming jamming, program selection and idle down.

2. Description of the Related Art

Upper and Lower Feed Stop

Some prior art brush chippers have only a manually controlled upper feedstop member with three positions, forward, neutral and reverse. Otherprior art brush chippers, particularly those used in Europe, also have alower feed stop member, having one shut-off position. This lower feedstop member is disposed just below the feed table and typically ispivotally attached to the frame and has a forward position and arearward position, forward being the front when considering thedirection of flow of the brush through the machine and rearward beingthe place where the brush enters the feed table. A problem with priorart devices is that when larger branches are inserted onto the feedtable that means that larger sub-branches will also emanate from suchbranch. These larger downwardly extending branches often hit the lowerfeed stop member and shut off the feed mechanism of the brush chipper attimes when the operator actually wants the feed mechanism to continue tooperate. In addition to size, the shape or stiffness of the downwardlyextending branches also affect whether the lower control bar isactivated. While these prior art brush chippers operate just fine whensmaller branches are fed into the brush chipper, the problem primarilyexists during the time that larger or stiffer sub-branches are being fedinto the brush chipper. It is perceived that if the machine isconstantly being shut off by the lower feed stop bar when largerbranches are being fed into the machine, there is a danger that anoperator might attempt to disable the shut off mechanism so that he cancontinue to finish the job of chipping larger branches without theinconvenience of having the brush chipper shut itself off frequently,i.e. nuisance stops.

Consequently, there is a need for a brush chipper having a lower feedstop member which will overcome the aforementioned disadvantages. Also,upper feed stop control members usually have only three positions,forward, neutral and reverse. This limits their usefulness, especiallyin combination with other aspects of the present invention.

Predictability

If a larger log is being chipped, the engine decelerates quickly andthis will stop the feed rollers more quickly than if a smaller log orbranches are being chipped. Prior art devices do not distinguish betweenthe two. There is an advantage in using this information in the controlof a brush chipper which advantage is not currently being used by theprior art.

Feed Roller Reversing

The engine needs to re-accelerate in order to work in an optimum manner.Even when the feed rollers are stopped from feeding material into thecutter mechanism, the engine rpm may not accelerate. This can be due todrag caused by a log or the like rubbing against the cutter mechanism.So merely stopping the feed rollers may not be sufficient to solve theproblem. The present invention presents a solution to this problem

Overcoming Jamming

In the prior art, occasionally, the material being fed into the chipperwill become oriented so it catches on the feed table, the infeedopening, or elsewhere. The hydraulically powered feed rollers will thenstall and the hydraulic oil will be redirected through the relief valve.Often the operator need only manually operate the upper feed control barto momentarily reverse the feed rollers and return to the forward feedposition to reorient the material so that it will continue feeding. Thepresent invention provides an automatic solution to this problem.

Program Selection

Controllers for brush chippers can have more than one program for usedepending upon certain parameters, such as the size of the engine, etc.The present invention provides an automatic solution to programselection which is not available in the prior art.

Idle Down

During the chipping process, there are times when the chipper is runningat a high rpm but is not being used for chipping. This could be due toan operator hauling branches to the chipper, moving the chipper toanother location, or the operator being distracted for some reason andnot using the chipper. This causes fuel to be used unnecessarily andcauses unnecessary wear and tear on the brush chipper. The presentinvention provides an automatic solution to this problem.

BRIEF SUMMARY OF THE INVENTION Lower Feed Stop Bar

The present invention relates generally to a brush chipper having aframe with cutting members for cutting tree branches, the cuttingmembers being operatively attached to the frame. At least one rotarymember is operably mounted to the frame for pulling the tree branchestoward the cutting members so the branches can be cut into smallerpieces. A feed table is operably and pivotally attached to the frame forselective movement between a transport position and an operativeposition for supporting the branches and guiding them toward the rotarymember. A lower feed stop member is operably attached to the front endof the feed table. This lower feed stop member has a forward position,an intermediate position and a rearward position.

A shut-off mechanism is operatively attached to the feed table and tothe lower feed stop member for shutting off the rotation of the rotarymember when the lower feed stop member moves from the rearward positionto a predetermined one of said forward or intermediate positions,whereby when the lower feed stop member moves to the predeterminedposition, the shut-off member will stop the rotary feed member. Thepredetermined setting of the lower feed stop member is adjustable by theoperator, depending upon the working conditions, and is provided with amechanism for automatically re-setting the predetermined setting afteruse of the brush chipper and before it is used again.

Upper Feed Stop Bar

An improved upper feed control member and an associated control systemis provided also for controlling the rotary feed member. This upper feedcontrol bar has four positions instead of three. It has a stop positionfor stopping the rotary feed member, a forward position, for causingforward feed of the rotary feed member by rotation in one direction, aneutral position when moved in the other direction from forward feed anda reverse position when moved from neutral in such other direction forcausing the rotary feed member to rotate in a direction reverse from theone direction thereby causing brush in the rotary feed rollers to bebacked away from the cutters.

Predictability

The present invention predicts the feed roller shutoff point accordingto the rate of engine/drum deceleration. If a larger log is beingchipped, the engine decelerates quickly, and the controller will stopthe feed rollers at a higher engine rpm. If branches or a smaller logare being chipped, the engine will decelerate slowly, and the controllerwill stop the feed rollers at a lower engine rpm. Stopping the feedrollers at a higher rpm when chipping larger logs prevents the enginespeed from dropping too low. Low engine speed causes plugging due toinadequate velocity for the chips to clear the cutter mechanism.Conversely, stopping the feed rollers at a lower rpm when chippingsmaller material allows the machine to continue chipping, thus making itmore productive.

Feed Roller Stop and Reverse

When the controller of the present invention tells the feed rollers tostop feeding material into the cutter mechanism, the engine needs toaccelerate, but material could be rubbing against the cutter mechanism,causing drag. In the broadest form of the feed roller stop and reverseaspect of the prevent invention, to overcome this drag on the cuttermechanism, the present invention not only stops the feed rollers, butalso reverses them for a short period of time. This pulls the materialaway from the cutter mechanism, eliminates the drag, and enables theengine to accelerate quicker.

Another optional feature of this aspect of the present inventioninvolves reversing more than once. Once the feed rollers reverse once,if the engine does not begin accelerating soon, it could be due toself-feeding, that is, pulling the material into the cutter mechanismeven though the feed rollers are attempting to hold the material back.If this occurs, the present invention will reverse the material againfor a second short period of time. This can be programmed to happen morethan two times if necessary.

Overcoming Jamming

Occasionally, the material being fed into the chipper will be orientedso it catches on the feed table, the infeed opening, or elsewhere. Thehydraulically powered feed rollers will then stall and the hydraulic oilwill be redirected through the relief valve. Often the operator needonly manually to operate the upper feed control bar to momentarilyreverse the feed rollers and return to the forward feed position toreorient the material so that it will continue feeding. The presentinvention does this automatically, without operator input. A pressureswitch is put into the relief valve circuit so when the feed rollersstall and the oil goes over relief, the switch is tripped. The trippedswitch signals the controller to momentarily reverse the feed rollers,and to continue to cycle (reverse, then forward) the feed rollers todislodge the material, until the chipper resumes feeding.

Self Diagnosis and Program Selection

Controllers for brush chippers can have more than one program for usedepending upon certain parameters, such as the size of the engine, etc.The present invention is set to recognize certain resistors and selectthe automatic program, but could set itself by other parameters. Forexample the first time that the engine is throttled over 1500 rpm's, thecontroller could take the rpm that is stable for more than apredetermined time, say three seconds, and designate it as “High Idle,No Load”. It would then set the feed roller start point accordingly.When the chipping is started, the controller will measure the time fromfeed roller stop to feed roller start and continually adjust the feedroller stop point so this amount of time is consistent to a presetamount.

Idle Down

During the chipping process, there are times when the chipper is runningat a high rpm but is not being used for chipping. This could be due toan operator hauling branches to the chipper, moving the chipper toanother location, or the operator being distracted for some reason andnot using the chipper. This causes fuel to be used unnecessarily andcauses unnecessary wear and tear on the brush chipper. The presentinvention provides a selector switch which allows the operator to selectan “Idle Down” feature. If this is selected, the controller willautomatically idle the engine down to low idle, with the feed rollersturning, if nothing has been fed into the chipper for a pre-selectedperiod of time. This is sensed either my monitoring engine speed or by alimit switch on the feed roller slides that indicates when they open.When the operator approaches the machine with more material to chip, hewould insert the material into the feed roller, causing the feed rollersto open slightly. The feed rollers would then stop while the enginespeed returns to the recovery point, after which regular chippingresumes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a brush chipper constructed inaccordance with the present invention;

FIG. 2 is a perspective view of a pivotable feed table on the rear ofthe brush chipper of FIG. 1;

FIG. 3 is an enlarged perspective view of the rear left corner of thefeed table of FIG. 2 showing a portion thereof broken away to show how aspring biases a lower feed stop member to a rearward position as shownin FIG. 3;

FIG. 4 is a side elevational cross sectional view of cam-operatedswitches used to turn off the feed rollers of the brush chipper undercertain circumstances when the lower feed stop member is pivoted;

FIG. 5 is a view from under the feed table of FIG. 2 showing anotherview of the cam and switches in a position the same as FIG. 4, but whichis the rearward most position of the feed stop bar when both switchesare closed, permitting the brush chipper feed rollers to operate undermost conditions;

FIG. 6 is a view like FIG. 4 but showing the feed stop bar pivoted to anintermediate position corresponding to normal sensitivity wherein thenormal sensitivity switch is allowed to be open and the reducedsensitivity switch is closed;

FIG. 7 is a view like FIG. 5 but showing the lower feed stop member, camand switches in the position shown in FIG. 6;

FIG. 8 is a view like FIGS. 4 and 6 but showing the lower feed stopmember in the forward most position thereby allowing both of theswitches to move to the open position thereof corresponding to reducesensitivity;

FIG. 9 is a view like FIGS. 5 and 7 but corresponding to the position ofthe lower feed stop member, cam and switches shown in FIG. 8, thatposition being the forward most position of the lower feed stop member;

FIG. 10 is an enlarged perspective view from the right rear side of thebrush chipper as shown in FIG. 1 and showing the upper feed controlmember having a linkage pivotally connected to a cam which is pivotallyconnected to the machine for controlling the position of three switches;

FIG. 11 is a view of the upper feed stop member linkage and cam shown inthe forward feed position which under most circumstances permits thefeed rollers to pull brush into the brush chipper of FIG. 1;

FIG. 12 is a view like FIG. 11 but showing the upper feed control memberpulled rearwardly to a stopped position whereby a normally open stopswitch is pushed to the closed position thereof;

FIG. 13 is a view like FIGS. 11 and 12 but showing the upper feedcontrol member pushed all the way forward to a reverse position whichcauses the feed control rollers to rotate to pull brush out of the rearof the brush chipper under most conditions and also resets the circuitso it can be used again after having been to the stop position of FIG.12;

FIG. 14 is a view like FIGS. 11-13 but showing the cam and upper feedcontrol member in the neutral position wherein none of the switches aremoved to the closed position thereof and wherein the forward feedrollers are stopped but ready to be either reversed or moved to theforward feed position of FIG. 11;

FIG. 15 is a schematic electrical diagram of the feed roller control;

FIG. 16 is a flow chart of the feed roller control of FIG. 15;

FIG. 17 is an electrical schematic diagram of the lower feed stop barsensitivity circuit;

FIG. 18A is the top part of a lower feed bar sensitivity flow chart asillustrated in FIG. 17;

FIG. 18B is the bottom part of the lower feed stop bar sensitivity flowchart as illustrated in FIG. 17;

FIG. 19 is an electrical schematic diagram of the predictability aspectof the present invention;

FIG. 20 is a flow chart illustrating the operation of the forward feedrollers as illustrated in FIG. 19;

FIG. 21 is an electrical schematic diagram of the feed roller stop andreverse aspect of the present invention; and

FIG. 22 is a flow chart of the operation of the feed roller stop andreverse aspect shown in schematic diagram of FIG. 21;

FIG. 23 is an electrical schematic diagram of the overcoming jammingaspect of the present invention;

FIG. 24 is a flow chart illustrating the way the overcoming jammingschematic of FIG. 23 operates;

FIG. 25 is an electrical schematic diagram of the program selectionaspect of the present invention;

FIG. 26 is a flow chart of the program selection aspect of the programselection of the present invention;

FIG. 27 is a flow chart of the “idle down” aspect of the presentinvention; and

FIG. 28 is an enlarged partial cross sectional view taken along line28-28 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIG. 1shows a brush chipper (10) constructed in accordance with the presentinvention and having a feed table (11) on the rear thereof. A frame (12)has wheels (13) rotatably attached thereto to permit the brush chipper(10) to be moved from place to place. A housing (14) has cutters (15)which cut brush that enters the feed table (11), which brush is pulledtherethrough by feed rollers (16) and delivers the brush to the cuttersto cut the brush and throw chips out a discharge chute (17).

The feed table (11), as shown in FIGS. 1 and 2, has a bottom portion(21) and side portions (22) and (23). A hinge (24) pivotally attachesthe feed table (11) to the frame (12). An upper feed control member (26)is pivotally attached at rod (27) to the frame (12). The feed table (11)is in the operative position shown in FIG. 1, but would be pivotedupwardly to place it in a transport position wherein the brush cutter(10) could be towed from place to place using a tongue and hitch (notshown). The upper feed control member also has handles (28) which can begrasped by the operator if desired.

Lower Feed Stop Bar

The bottom of the feed table (21) is chamfered downwardly at lip (29). Alower feed stop member (31) is pivotally attached at point (32) by a rod(33) that extends across and through side member (22) of the feed table(11). One end (30) of a coiled tension spring (34) is attached into andthrough a slot in rod (33) and has an end portion (35) bearing againstthe bottom of the feed table floor (21). This biases the lower feed stopbar (31) to the rearward most position as shown in FIGS. 2, 3, 4 and 5.The rod (33) is rigidly attached to a plate (36) on the left side of thefeed table (11) as shown in FIG. 2. This plate (36) also has a cam (37)welded thereto for movement with the lower feed stop member (31).

Looking to FIGS. 2 and 3, it will be noted that the lower feed stopmember (31) is strategically placed to extend a predetermined distanceoutwardly from the lip (29) of the floor (21) of the feed table (11).This is important to the operation of the lower feed stop member as willbe discussed below.

FIG. 4 shows the plate (36) in dashed lines, which is rigidly attachedto the lower feed stop member (31) and which pivots together with rod(32) because they are rigidly attached to each other. A kidney-shapedopening (45), which is shown in dashed lines in FIGS. 4-8 but which canbe seen in solid lines in FIGS. 7 and 9, permits the cam (37) to extendthrough and be moved along an arc within the kidney-shaped opening (45)in the side panel (22) of the feed table (11). FIG. 5 shows theextension (30) on one end of spring (34) which is similar to theextension (35) on the other end of the spring (34) that extends througha slot in shaft (32) as referred to above. FIGS. 3, 4 and 5 show thelower feed stop member (31) in the rear most position to which it isbiased by the spring (34). So long as it is in this position, this feedstop bar will not shut off the feed rollers (16), although the feedrollers (16) can be shut off in other ways which will be describedbelow.

The purpose of the lower feed stop bar (31) is to shut off the feedrollers when something pushes against the bar (31) and overcomes thebias of the spring (34) to such an extent that it moves the bar (31) toeither an intermediate position shown in FIGS. 6 and 7 or a forward mostposition shown in FIGS. 8 and 9 and, depending on the sensitivityselection, will then stop the feed rollers (16). Flange (38) shown inFIG. 28 serves as a stop to prevent lower feed stop bar (31) frompivoting too far forwardly.

Sometimes a large log on the feed table floor (21) will have adownwardly extending branch which will contact the lower feed stop bar(31), which will shut off the feed roller (16) under certaincircumstances. Also, the operator of the brush chipper (10) can alsoshut off the feed roller (16) by pushing on the lower feed stop bar(31). This can be done either intentionally or inadvertently and thefeed rollers (16) will shut off if the bar (31) is pivoted to apredetermined position as will be explained below. The forcespotentially acting on the lower feed bar (31), specifically from thedownwardly extending branches, can be sufficient to damage the lowerfeed bar (31), particularly if it were simply supported on the ends.FIG. 28 illustrates the preferred embodiment of the mechanical designthat provides for a full length stop which provides support for the stopbar (31). Plates (38) and gusset (39) are located in a manner relativeto flange (29) to define a structural member that is full width. Whenlower feed bar (31) pivots forwardly (to the left as viewed in FIG. 28)plate (38) acts as a stop when and if lower feed bar (31) strikes plate(38).

FIG. 4 shows a lower feed stop bar normal sensitivity switch (418). Thisswitch (418) is spring biased outwardly to a normally open position.Similarly, a lower feed stop bar reduced sensitivity switch (420) is thesame type of switch and has a shaft (41) and a roller (42) rotatablyattached by a pin (43) to the shaft (41). In FIGS. 4 and 5, both of theswitches (418) and (420) are being held closed by the cam (37) and, ofcourse, they will not shut off the feed roller (16) when they areclosed, which corresponds to the rearward position of the lower feedstop member (31) in FIGS. 3, 4 and 5. The rearward position of member(31) is the position to which it is biased by spring (34).

Referring now to FIGS. 17, 18A and 18B, in conjunction with FIGS. 3-9,the operation of the lower feed stop bar will be explained. Referring toFIG. 17, a controller (410) has various inputs and includes a battery(400) and a fuse (408). Also shown in the circuit is a lower feed stopbar switch with normal sensitivity (418), a lower feed stop bar switchwith reduced sensitivity (420) and an upper feed control bar stop switch(422). A relay (444), a selector switch (446) and a caution light (442)are also shown in the circuit. The caution light (442) can also be seenon the panel in FIG. 1.

Referring now to FIGS. 18A and 18B, which are merely the top and bottomportion of the lower feed bar sensitivity operating flow chart, showsthat at the start the operator needs to choose by operating sensitivityselector switch (446) whether to operate in a normal mode or a reducedsensitivity mode. It is to be understood that the present invention willdefault to the normal sensitivity in one of a number of ways such aswhen the machine is turned on and off and/or when the feed table (11) ispivoted up or down. This default can be accomplished in other ways aswell and still be covered by the attached claims. Under normalconditions, the machine will have defaulted to normal sensitivity byswitch (446) and typical chipping operation continues. The operator willthen operate the upper feed control member (26) in a way which will beexplained later and is explained in detail in FIGS. 15 and 16. Assumingthe chipping continues in a situation where the operator has activatedthe forward feed rollers, the chipping continues unless the operatorchooses a different sensitivity setting or shuts down the machine.Following through steps (228), (234) and (238) of FIGS. 18A and 18B, itis noted that the lower feed stop member is tripped at the early tripposition as shown in FIGS. 6 and 7. This could, for example, be when thelower feed stop bar is 30 degrees from a vertical line through the pivotpoint of shaft (32) of the lower feed stop member (31). That means, ofcourse, that when in the rearmost position, the feed stop member wouldbe more than 30 degrees from the vertical line. Of course other degreesof pivoting can be chosen, 30° being given as an example only for normalsensitivity.

Step (238) of FIG. 18B corresponds to FIGS. 6 and 7. At this pivoting offor example 30°, the normal sensitivity switch (418), which has beenpreviously selected or defaulted to, loses contact with the cam (37),and because of the spring therein, pivots outwardly to the positionshown in FIGS. 6 and 7. This is the open position of the switch (418),thereby signaling the controller causing the feed rollers (16) to stop.This is illustrated in block (242) of FIG. 18B. With the feed rollersstopped, the operator can rectify the problem by removing the brush, orwhatever has caused pressure against the lower feed stop bar (31).

In instances where large logs are being fed into the brush chipper (10),the large branches emanating therefrom may cause the brush chipper tooccasionally trip the lower feed stop bar (31) in the normal sensitivitymode of FIGS. 3 and 4. In such a case, the operator may choose to usethe sensitivity selector switch (446) in FIG. 17 to reduce thesensitivity of the lower feed stop bar by selecting to use switch (420).In such a case, the movement of the bar (31) to the position shown inFIGS. 6 and 7 will not shut off the feed rollers (16), because switch(418) is not being used. Instead, switch (420) is in the circuit so thatfurther pivoting to the forward most position shown in FIGS. 8 and 9(e.g. 15 degrees from vertical) is required before the switch (420) willmove to the open position thereof. Movement of the lower feed stop bar(31) and the cam (37), which is rigidly attached thereto, allows theswitch (420) to open.

Referring back to the flow chart of FIGS. 18A and 18B, from the start(222) to (226), the reduced sensitivity option to the right has beenchosen. At option (230), trapezoidal box, which shape indicates operatorcontrol, shows that the operator has selected reduced sensitivitythrough the switch (446). At box (232), the reduced sensitivity alertlight (442) is on so that the operator is constantly reminded that he isusing the reduced sensitivity mode. Then the chipping continues as shownin block (236) of FIG. 18A. At (240), chipping continues or the operatorchooses to change the sensitivity setting or shut down the machine. Ifthe operator continues with reduced sensitivity, block (248) indicatesthat the lower feed bar can be tripped at the late trip position. Forexample, if the lower feed stop bar (31) pivots to 15°, whichcorresponds to FIGS. 8 and 9 in block (252) of FIG. 18B, the feedrollers (16) will be stopped because switch (420) is then open. Theoperator will then exit to the feed roller control (254) of FIG. 16.Referring to part (240) of the FIG. 18B flow chart, if the operatordecides to go back to normal sensitivity, for example because smallerbrush is being chipped, then the operator at (246) would push thesensitivity selector switch (446) to move it back to normal sensitivity.At (250) in FIG. 18B, the reduced sensitivity light (442) will go outand typical chipping operation resumes.

FIGS. 10-14 show more detail about the upper feed control member (26)and how it operates. Referring specifically to FIG. 10, a cam (51) ispivotally attached at point (52) to a plate (53). A slot (54) in the cam(51) has a post (56) extending therethrough and this cooperation betweenpost (56) and slot (54) limits the amount of movement for pivoting ofthe cam (51). Post (56) is rigidly attached to plate (53). The cam (51)has a projection (57) on one side thereof and a pair of depressions ordetents (58) and (59) on the other side thereof, separated by aprojection (61). A cam follower (62) is pivotally attached about point(63) and has a roller (64) which follows the edge of the cam (51) on theleft side as shown in FIG. 10. This cam follower (62) is biased by acompression spring (66) toward the cam (51).

A linkage (67) is pivotally attached at fastener (68) to the top of thefeed control member (26) and at the bottom by fastener (69) to the topof the cam (51). FIGS. 10 and 11 show the position of the upper feedcontrol member (26) and cam (51) in the forward feed position indicatedby the follower (64) being in the upper detent (58) and switch (414)being depressed to the closed position. Switches (414), (422) and (424)are normally open switches just like switches (418) and (420) of FIGS.15 and 5-9.

If the operator wishes to stop the feed rollers (16) of FIG. 2, theoperator would pull back the upper feed control member (26) to theposition shown in FIG. 12 which will move the cam (51) to the stopposition shown in FIG. 12 and will open the upper feed control stopswitch (422), thereby stopping the feed rollers (16). When that occurs,the feed rollers (16) cannot rotate again until the operator pushes theupper feed control member (26) forwardly to the position in FIG. 13,which is the reverse position. Reverse position is also a resetposition. Reset allows for the feed rollers (16) to be able to beactivated again. There follows, only after reset, a predetermined timewhen the stop input is ignored as illustrated at step (218) in FIG. 16.This allows branches to move past the lower stop bar and reducesinadvertent stops resulting when the operator overshoots the intendedposition of the upper feed control bar, thereby inadvertently andmomentarily hitting the stop position.

When the cam (51) is in the position shown in FIG. 13, projection (57)closes the switch (424), which is the reverse feed switch, and causesthe feed roller (16) to move in a reverse rotation to cause brush to bemoved rearwardly over the feed table floor (21) shown in FIG. 2. Thefeed control member (26) will remain in the reverse position of FIG. 13without help from the operator, requiring a constant force by theoperator to maintain the positions of FIGS. 11 and 14.

If the operator wants to move from the reverse position, the nextposition is shown in FIG. 14, the neutral position, wherein none of theswitches (414), (422) or (424) are in contact with projection (57) whichplaces the switches in their normal state as illustrated in FIG. 15. Inthe neutral position the roller (64) is in the lower detent (59), makingit easier for the operator to keep it in the neutral position of FIG. 14than in the reverse position of FIG. 13.

Referring to FIG. 11, it is noted that the operator can easily leave theupper feed control bar (26) in the forward feed position, which is aposition in which the machine is operating to cut brush because theroller (64) is in the detent (58) of cam (51).

Referring now to FIG. 15, a feed roller control circuit diagram isshown, having a battery (400) and a fuse (402). Also fuses (406) and(408) are in the circuit leading from ignition switch (404) to thecontroller (410). An engine speed sensor switch (412) is in the circuitas are upper feed control member forward feed switch (414), forward feedsolenoid (416), lower feed stop member normal sensitivity switch (418)and lower feed stop switch with reduced sensitivity (420). Switch (422)is an upper feed control member switch for stopping the feed roller(16). Upper feed control member reverse feed switch (424) is connectedin series with reverse feed solenoid (426), which controls hydraulicfluid to the hydraulic motors for use in rotating feed rollers (16) inone direction or the other.

Referring to FIG. 16, start is at (200). At block (202), the stopcircuit is tripped by either the lower feed stop bar (31) being hit orthe upper feed control member being moved to the stop position of FIG.12. Step (204) asks the question “Has the stop circuit been tripped.” Ifthe answer is “yes”, then the operator moves the upper feed controlmember to reverse at step (206), which is the same as the reset positionof FIG. 13. This resets the circuit. There follows a predeterminedperiod of time at step (218) where the stop circuit is ignored. Thechipper (10) can then be operated again. Looking to part (204) of theflow chart of FIG. 16, if the stop circuit has not been tripped, step(208) asks the question “Is the upper feed control bar in forward,reverse, or neutral.” If the upper feed control member is in reverse,the step (212) shows that the feed rollers (16) are rotating in reverse.If the upper feed control member is in neutral, step (214) indicatesthat the feed rollers are not rotating. If the upper feed control memberis in the forward position of FIG. 11, then step (216) indicates thatthe feed rollers (16) will rotate forwardly, however, if the answer tothe question of (210), “Is the engine speed above the recovery point”,is “no”, the engine will be allowed to accelerate until that answer is“yes”, in which case the feed rollers will begin to rotate forwardlyagain.

Predictability

Referring now to FIGS. 19 and 20, another aspect of the presentinvention will be explained. The controller (410) is also set to utilizethe predictability logic chart of FIG. 20. Referring to FIG. 20, it isnoted that at the start (260) the engine speed sensor (412) will monitorthe engine rpm as indicated at (262). The controller (410) willcalculate the rate of engine deceleration, i.e. speed verses a fixedtimer interval. At (266) the question is asked “Will the engine speed bebelow the droop threshold at the next time interval?” If the answer is“yes”, then at (268) the question is “Are the feed rollers currentlyfeeding material?” If the answer is “no”, then the controller goes backto monitoring the engine speed rpm. If the answer is “yes” the feedrollers are stopped at (272), referring back to FIG. 22.

Going back to (266), if the answer is “no”, then at (270) the questionis “Are the feed rollers already feeding?” If the answer is “yes” then(262) the engine rpm is monitored. If the answer is “no”, then questionis asked at (274), “Is the engine speed above the recovery point?” Ifthe answer is “no”, the rpm is monitored. If the answer is “yes”, at(276), the feed rollers (16) are started.

Consequently, using this predictability feature, the present inventionpredicts the feed roller shut off point, according to the rate of enginedeceleration. If a larger log is being chipped, the engine deceleratesquickly and the controller (410) will stop the feed rollers (16) at ahigher engine rpm. If branches or a smaller log are being chipped, theengine will decelerate slowly and the controller (410) will stop thefeed rollers at a lower engine rpm. Stopping the feed rollers at ahigher rpm, when chipping larger logs, prevents the engine speed fromdropping too low. Low engine speed causes plugging of the chipper due toinadequate velocity for the chips to clear the cutter mechanism.Conversely, stopping the feed rollers (16) at a lower rpm when chippingsmaller material, allows the machine to continue chipping, thus makingit more productive.

Feed Roller Stop and Reverse

Referring now to FIGS. 21 and 22, a feed roller stop and reverse aspectof the invention will be discussed. FIG. 21 shows the controller (410)with the engine speed sensor (412) upper feed control member forwardfeed switch (414), forward feed solenoid (416) and reverse feed solenoid(426). Referring now to FIG. 22, the flow chart indicates that at thestart (280) and at (282), the feed rollers are stopped. At (284) thefeed rollers are reversed for a short, predetermined amount of time.This reversal of just once constitutes the broadest aspect of thisinvention. Another aspect of the invention involves more than onereversal. In the preferred embodiment shown in FIGS. 21 and 22, thequestion, also at (284), is asked—“Does the engine speed continue todrop?” If the answer is “no”, that is the end (290). If the answer is“yes”, at (288), the feed rollers are reversed for a longer,predetermined amount of time. When the controller (410) of the presentinvention tells the feed rollers (16) to stop feeding material into thecutting mechanism, the engine (20) needs to accelerate, but materialcould be rubbing against the cutter mechanism causing drag. To overcomethis drag on the cutter mechanism, the present invention not only stopsthe feed rollers (16), but also reverses them for a short period oftime. This pulls the material away from the cutter mechanism, eliminatesthe drag, and enables the engine to accelerate quicker. Once the feedrollers (16) reverse, if the engine does not begin accelerating soon, itcould be due to “self-feeding”, that is, pulling the material into thecutter mechanism even though the feed rollers (16) are attempting tohold the material back. If this occurs, the present invention willreverse the material again for a second short period of time.

Overcoming Jamming

Referring now to FIGS. 23 and 24, the aspect of overcoming jamming willbe discussed. FIG. 23 shows the important part of the circuit for thisaspect of the invention, including a hydraulic overpressure switch(492). Referring now to FIG. 24, at the start (300), there is at (302) atypical chipping operation. Then the question is asked at (304), “Hasthe feed roller hydraulic system been overpressured for a predeterminedamount of time?” If the answer is “no” then typical chipping operationcontinues at (302). If the answer is “yes” then at (306) the feedrollers (16) are momentarily reversed. At (310), the question is asked“Has the feed roller hydraulic system pressure returned to normal?” Ifno, the question is continuously asked again until the answer is yes. At(308), after the reversing, the feed rollers (16) resume forwardrotation and typical chipping operation continues at (302) after it hasbeen determined that the hydraulic system is no longer overpressured.

The hydraulic overpressure switch is a means for sensing the speed ofthe feed rollers. Other means for sensing the speed of the rollers arefully equivalent to the hydraulic sensing means.

The hydraulic overpressure switch is a means for sensing the speed ofthe feed rollers. Other means for sensing the speed of the rollers arefully equivalent to the hydraulic sensing means. For example, a speedsensor can be used to measure the speed of the feed rollers (16) and seta threshold speed which defines “jamming”. A rotation sensor could alsobe used. Another alternative would be to have a shaft drive, a brakedisc, a brake pad with a small force act against the disc, have thisbrake pad assembly spring loaded, a switch operative with the mechanismsuch that if the shaft were turning the brake pad assembly, it will bepulled in one direction stretching the spring and activating the switchwhile with no rotation, the brake pad assembly would be pulled in theopposite direction by the spring contracting and deactivating theswitch.

Occasionally, the material being fed into the chipper will be orientedso it catches on the feed table (11), the infeed opening, or elsewhere.The hydraulically powered feed rollers (16) will then stall and thehydraulic oil will be re-directed through the relief valve (not shown).Often the operator need only manually operate the upper feed control barto momentarily reverse the feed rollers (16) and then return to theforward feed position to re-orient the material so that it will continuefeeding. The present invention, however, does this automatically,without operator input. A pressure switch (492) is put into the reliefvalve circuit so that when the feed rollers (16) stall and the oil goesover relief, the switch (492) is tripped. The trip switch (492) signalsthe controller (410) to momentarily reverse the feed rollers, and tocontinue to cycle (reverse, then forward) the feed rollers to dis-lodgethe material, until the chipper can resume operation. An alternativeembodiment that is not illustrated would include the use of a rotationsensor or speed sensor capable of measuring speed of the feed rollers,or checking for rotation, or lack thereof, of the feed rollers. Thisinput could then be utilized rather than input from pressure switch(492) in exactly the same manner, as is understood by one of ordinaryskill in the art.

Program Selection

Also part of the controller (410) is a program selection feature shownin FIG. 25 which additionally has machine designator resistors (516) and(518). This allows the one controller (410) to be used on differentmachines to operate somewhat differently when it senses which machine itis on, e.g. the one indicated by resistor (516), or the one indicated byresistor (518).

Referring now to FIG. 26, at the start (320), the power-up of thecontroller is indicated at (322). At (324) the controller (410) willread the machine designated resistors (516) or (518) (of course therecould be more than two resistors). The controller (410) at (326) willthen select the correct program for the machine corresponding to theresistor that is present on that machine. At (328), the typical chippingoperation will continue wherein the controller (410) will know whichprogram it is to use, depending upon which machine is being controlled.This program selection could be set by other parameters. For example,the first time that the engine is throttled over a predetermined rpm,the controller could take the rpm that is stable for more than apredetermined time, for example three seconds, and designate it as “highidle, no load”. It would then set the feed roller start pointaccordingly. When the chipping is started, the controller (410) willmeasure the time from feed roller stop to feed roller start andcontinually adjust the feed roller stop point so this amount of time isconsistent to a pre-set amount. Controller (410) can select a program touse based on this information.

Idle Down

Referring now to FIG. 27, there is the start (340), and then there is(342) for a typical chipping operation. The question is asked at (344),“Has the machine remained unused for a predetermined amount of time?” Ifthe answer is “no”, typical chipping operation continues. However, ifthe answer is “yes”, at (346), the engine speed is reduced to idle andthe feed rollers continue to rotate. When the operator at (348) insertsmaterial into the feed rollers (16) and they move apart (350), the feedrollers (16) are stopped while the engine returns to an operating rpm,at which time at (352) the feed rollers (16) start and (342) typicalchipping operation continues.

During the chipping process, there are times when the chipper is runningat a high rpm but is not being used for chipping. This could be due toan operator hauling branches to the chipper, moving the chipper toanother location, or the operator being distracted for some reason andnot using the chipper. This causes fuel to be used unnecessarily andcauses unnecessary wear and tear on the brush chipper (10). The presentinvention provides a selector switch which allows the operator to selectan “idle down” feature. If this is selected, the controller willautomatically idle the engine down to low idle, with the feed rollers(16) turning, if nothing has been fed into the chipper (10) for apre-selected period of time. This is sensed either by monitoring enginespeed or by a limit switch on the feed roller slides that indicate whenthey are open. When the operator approaches the machine with morematerial to chip, he would insert the material into the feed rollers(16), causing the feed rollers (16) to open slightly. The feed rollers(16) would then stop while the engine speed returns to high idle, afterwhich regular chipping resumes.

Obviously many modifications and variations of the present invention arepossible in light of the above teachings. It is therefore to beunderstood that, within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

1. A method of controlling a brush chipper of a type having an engine,an engine speed sensor, cutters, feed rollers and a forward feedcontrol, the method comprising: stopping the feed rollers because theengine speed has dropped below a predetermined speed; reversing the feedrollers for a predetermined period of time; if the engine speedcontinues to drop, reverse the feed rollers for a second predeterminedperiod of time; and if the engine speed is above a recovery point, startthe feed rollers in a forward direction.
 2. A method of controlling abrush chipper of a type having an engine, an engine speed sensor,cutters, feed rollers and a forward feed control, the method comprising:sensing an engine speed; calculating a rate of change of the enginespeed with time; estimating, based on the rate of change of the enginespeed with time, if the engine speed will drop below a predeterminedspeed in a predetermined increment of time; stopping a forward rotationof the feed rollers if it is estimated the engine speed will drop belowthe predetermined speed in said predetermined increment of time;reversing the feed rollers for a predetermined period of time; andoperating the feed rollers in a forward direction to deliver brush tothe cutters.
 3. A method of controlling a brush chipper of a type havingan engine, cutters, feed rollers, and means for sensing the speed ofsaid feed rollers, the method comprising: operating the feed rollers andcutters to cut brush; if said feed rollers are slowed by a predeterminedamount or stopped, momentarily reversing the feed rollers for apredetermined period of time; and resuming operation of the feed rollersto cut brush.
 4. The method of claim 2 additionally comprisingcontinuing a reversed rotation of the feed rollers if it is estimatedthe engine speed will be below the predetermined speed in saidpredetermined increment of time.